Financial education
How Debt Payoff Calculations Work
Debt payoff math depends on balance, interest rate, payment size, and how often interest is applied.
How the math works
A fixed monthly payment against a balance with interest determines a payoff timeline through the same math as a loan, solved in reverse: instead of solving for the payment, the calculator solves for how many months it takes at a given payment to reach zero.
Worked example
A $6,000 balance at 19.99% APR with a $200/month payment takes about 37 months and costs roughly $1,344 in interest. Raising the payment to $300/month cuts that to 22 months and about $746 in interest — nearly half.
What to watch for
- If the payment barely covers the month's interest, the payoff time becomes extremely long or the balance never actually falls
- Adding new charges to the balance resets the math — the payoff estimate assumes no new spending
- Introductory low-rate periods eventually expire and change the real payoff timeline
Practical takeaway
Even a modest increase in the monthly payment usually cuts both the payoff time and total interest by a large margin — check that trade-off before assuming you can't pay faster.